What is the best way to uniquely identify a DOM node ?

Question

What is a way to uniquely identify all DOM nodes in an HTML document. To illustrate what I mean, here is a (fictional) example:

• Script X randomly selects a DOM node from document.html.
• Script X needs to tell script Y which DOM node it has chosen.
• How does script X uniquely identify the DOM node it has chosen so that script Y knows exactly which node it is in document.html?

I'm really interested in how to uniquely identify the DOM node so that the script Y can identify it and manipulate it. Preferably, it should work with text nodes as well. I was thinking of XPath maybe, but I'm not sure how to generate a unique XPath to any given node.

Answer 1

Well, an XPath expression that results in a single node should be unique. What do you mean by "how to generate a unique XPath to any given node"?

Answer 2

You should be able to determine a unique XPath by working backwards from the node to the root node, and tracking the node you're on, and which sibling it is, such that you get something like:

/a[1]/b[2]/c[101]/text()

so that's the 101st C node under the second B node, etc. As such, that's a unique path and can be copied around with reference to the original document

Answer 3

Ordinal child positions along XPath axes. Nodes are strongly ordered, and so saying:

child 1 of child 3 of child 4 of child 5.

should do it.